Construction Of Biofunctional Magnetic Microsized And Nanosized Materials And Application In Immobilized Enzyme

Immobilized enzyme has been applied to numerous fields, including bioreactors, biocatalysts and biosensors because of its advantage such as good stability and reusability. There have many methods for preparation of immobilized enzyme, covalent combination has been widely adopted because of its excellence of combination fastness. But enzymatic properties of immobilized enzyme are different in connection with the different type of vector that has been selected. In this study, it has been put forward that taking reactive nanometer magnetic Fe304 particles as magnetic nucleus, and the copolymer of styrene(St)梐crylic acid(AA) as macromolecular shell, we could synthesize, magnetic polymer composite microspheres containing carboxyl groups on their surface, then microspheres are activated by thionylchloride, the surface of such magnetic composite microspheres thus produced had reactive acid chloride groups which then react with the free amino groups of the free soluble enzymes to give peptide bonds (桟O桸H?, finally enzyme is covalently immobilized. The reclaimed efficiency of immobilized enzyme that is prepared by thisvector is over 76%, but others are between 45% and 65%. It showsthat activated magnetic polymer composite microspheres is an efficient vector that can be applied immobilization field. The particular works are summarized as follows:1 The best preparation circuit was optimizedNH3?H20 was chosen to act as precipitating reagent, reactive nanometer magnetic Fe304 particles were prepared by co-precipitation method, the particles size distribution was between 20nm and 60nm through the detection of transmission electron microscope (TEM). The best preparation circuit was optimized through the combination process of precipitation and aging.2 With dispersion-polymerization, taking above reactive nanometer magnetic Fe304particles as nucleus, and the copolymer of styrene(St)梐crylic acid(AA) as macromolecular shell, we could synthesize, magnetic polymer composite microspheres containing carboxyl groups on their surface. In the process of synthesize, moisture compensation was fully considered and gel was prevented.3 Freundlich isothermal adsorption model was established. The model was based on the relationship between the concentration of freely soluble enzyme and adsorption quantity of the vector, combined with time and adsorption, some kineticparameters (IgK, n) related to the process were obtained by using the model.4 Immobilization process has no use for coupling reagent (e.g:glutaraldehyde).Apart from these, The factors involved with the enzymic properties of the immobilized papain were studied in comparison with freely soluble papain. The results showed that thermal and storage stabilities of the immobilized papain were higher than those of the freely soluble one, and that papain directly was immobilized onto the microspheres' surface without any spare space provided a higher stability. The optimum temperature, the pH and storage stability were 80癈, 8. 0 and 28 days respectively. The reclaimed efficiency of immobilized enzyme that is prepared by this vector is over 76%, the Michaelis - Menten kinetic constants were evaluated for the immobilized and the freely soluble enzymes, they were 21.64147 and 7. 0836, respectively.